CePMo 12 O 40 / TiO 2 catalysts for photocatalytic oxidation of methane to value‐added organic oxygenates

2021 ◽  
Author(s):  
Liyan Ming ◽  
Chunling Wang ◽  
Yun Hang Hu
Keyword(s):  
Photocatalytic Oxidation ◽  
Value Added ◽  
Oxidation Of Methane ◽  
Organic Oxygenates

scholarly journals Perspective tendencies in development of small scale processing of gas resources

2017 ◽  
Vol 89 (8) ◽  
pp. 1033-1047 ◽  
Author(s):  
Vladimir S. Arutyunov ◽  
Valery I. Savchenko ◽  
Igor V. Sedov ◽  
Alexey V. Nikitin ◽  
Ilya G. Fokin ◽  
...  
Keyword(s):  
Value Added ◽  
Small Scale ◽  
Oxidative Conversion ◽  
Direct Oxidation ◽  
Hydrocarbon Gases ◽  
Associated Petroleum Gas ◽  
Syngas Production ◽  
Oxidation Of Methane ◽  
Alternative Routes

AbstractThis paper analyses alternative routes for production of chemicals from different hydrocarbon gases by their direct, without syngas production, oxidative conversion to oxygenates or ethylene. Main of these routes are direct oxidation of methane to methanol (DMTM) and selective oxy-cracking of heavier natural or associated petroleum gas components which can be used for production of high value-added petrochemicals (in combination with carbonylation processes) and fuel gases, useful for gas piston engines. The advantages and practical capabilities of such technologies are discussed.

scholarly journals Enhancement of Photocatalytic Oxidation of Glucose to Value-Added Chemicals on TiO2 Photocatalysts by A Zeolite (Type Y) Support and Metal Loading

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 423 ◽  
Author(s):  
Kamonchanok Roongraung ◽  
Surawut Chuangchote ◽  
Navadol Laosiripojana
Keyword(s):  
Formic Acid ◽  
Surface Area ◽  
Gluconic Acid ◽  
Photocatalytic Oxidation ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Value Added ◽  
Incipient Wetness Impregnation ◽  
Microwave Assisted

TiO2-based photocatalysts synthesized by the microwave-assisted sol-gel method was tested in the photocatalytic glucose conversion. Modifications of TiO2 with type-Y zeolite (ZeY) and metals (Ag, Cu, and Ag-Cu) were developed for increasing the dispersion of TiO2 nanoparticles and increasing the photocatalytic activity. Effects of the TiO2 dosage to zeolite ratio (i.e., TiO2/ZeY of 10, 20, 40, and 50 mol %) and the silica to alumina ratio in ZeY (i.e., SiO2:Al2O3 of 10, 100, and 500) were firstly studied. It was found that the specific surface area of TiO2/ZeY was 400–590 m2g−1, which was higher than that of pristine TiO2 (34.38 m2g−1). The good properties of 20%TiO2/ZeY photocatalyst, including smaller particles (13.27 nm) and high surface area, could achieve the highest photocatalytic glucose conversion (75%). Yields of gluconic acid, arabinose, xylitol, and formic acid obtained from 20%TiO2/ZeY were 9%, 26%, 4%, and 35%, respectively. For the effect of the silica to alumina ratio, the highest glucose conversion was obtained from SiO2:Al2O3 ratio of 100. Interestingly, it was found that the SiO2:Al2O3 ratio affected the selectivity of carboxylic products (gluconic acid and formic acid). At a low ratio of silica to alumina (SiO2:Al2O3 = 10), higher selectivity of the carboxylic products (gluconic acid = 29% and formic acid = 32%) was obtained (compared with other higher ratios). TiO2/ZeY was further loaded by metals using the microwave-assisted incipient wetness impregnation technique. The highest glucose conversion of 96.9 % was obtained from 1 wt. % Ag-TiO2 (40%)/ZeY. Furthermore, the bimetallic Ag-Cu-loaded TiO2/ZeY presented the highest xylitol yield of 12.93%.

scholarly journals Laboratory-scale photomineralisation of n-alkanes in aqueous solution, by photocatalytic membranes immobilising titanium dioxide

2005 ◽  
Vol 7 (2) ◽  
pp. 79-85 ◽  
Author(s):  
Ignazio Renato Bellobono ◽  
Franca Morazzoni ◽  
Riccardo Bianchi ◽  
Emilia Simona Mangone ◽  
Rodica Stanescu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Oxidation ◽  
Point Of View ◽  
Laboratory Scale ◽  
Kinetic Constants ◽  
Quantum Yields ◽  
Oxidation Of Methane ◽  
Oxygen Donor ◽  
Absorbed Power ◽  
Kinetics Of

Kinetics of photocatalytic oxidation of methane, ethane,n-heptane,n-decane, andn-dodecane, to yield intermediates, and photomineralisation of intermediates, to yield carbon dioxide and water, was studied in aqueous solution, by a laboratory-scale photoreactor and photocatalytic membranes immobilizing30±3wt.% ofTiO2, in the presence of stoichiometric hydrogen peroxide as oxygen donor. The whole volume of irradiated solution was4.000±0.005L, the ratio between this volume and the geometrical apparent surface of the irradiated side of the photocatalytic membrane was3.8±0.1cm, and the absorbed power 0.30W/cm (cylindrical geometry). A kinetic model was used, by which mineralisation of substrate toCO2was supposed to occur, by kinetic constantsk1, through one single intermediate, mediating the behaviour of all the numerous real intermediates formed in the path from the substrate toCO2(kinetic constants of formation of the latter beingk2). A competitive Langmuirian adsorption of both substrate and “intermediate” was also supposed to be operative, as expressed by apparent adsorption constantsk1andk2, possessing a, partly at least, kinetic significance. By Langmuir-Hinshelwood treatment of initial rate data, starting values of thekandKcouples were obtained, from which, by a set of differential equations, the final optimised parameters,k1andk1,k2andK2, were calculated, able fit the whole photomineralisation curve, and not only its initial segment, as the Langmuirian parameters do. The parameters of present work are critically compared with those obtained in two preceding set of studies relative ton-alkanoic acids and ton-alkanols. They are interpreted on the basis of a closer behaviour of hydrocarbons to alkanols, from the photocatalytic point of view, than to carboxylic acids are. Discussion of limiting effective quantum yields, and their comparison with maximum, theoretical values, are also carried out.

Study on the Photo-Electro-Catalytic Oxidation of Methane

2013 ◽  
Vol 864-867 ◽  
pp. 1421-1426
Author(s):  
Wen Yan Wu ◽  
Luo Chun Wang ◽  
Zhen Zhou ◽  
Ke Jia Liu ◽  
Xiao Hua Li ◽  
...  
Keyword(s):  
Catalytic Oxidation ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Ambient Pressure ◽  
Kinetic Constant ◽  
Illumination Time ◽  
Oxidation Of Methane ◽  
Conversion Of Methane ◽  
Intermittent Illumination ◽  
Electro Catalytic Oxidation

Emission control of methane from landfills has received considerable attentions in recent years. Photo-electro-catalytic oxidation of methane was carried out at the mode of continuous electrolysis and intermittent illumination with TiO2-coated titanium mesh plate as pholocatalyst and electrode in combination with ionic liquid as electrolyte under UV light irradiation. The result showed that the rapid conversion of methane was achieved under ambient pressure and temperature through photocatalytic oxidation combining with electrolysis. Under the mode of intermittent illumination (on:off = 10 min : 10 min) and continuous electrolysis (II-CE), the highest oxidation rate of methane (280 mg/(m3min)) was obtained. Under fixed off time and total illumination time, the oxidation quantity of methane linearly increased with the intermittent frequency. Photo-electro-catalytic oxidation of methane can be described by the first-order kinetics, and the apparent kinetic constant increased with the intermittent frequency.

scholarly journals Selective electrochemical oxidative coupling of methane mediated by Sr2Fe1.5Mo0.5O6-δ and its chemical stability

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Kannan P. Ramaiyan ◽  
Luke H. Denoyer ◽  
Angelica Benavidez ◽  
Fernando H. Garzon
Keyword(s):  
Chemical Stability ◽  
Oxidative Coupling ◽  
Earth Metal ◽  
Value Added ◽  
Oxidative Coupling Of Methane ◽  
Oxidation Products ◽  
Oxidation Of Methane ◽  
Conversion Rates ◽  
Conversion Of Methane ◽  
Set Up

AbstractEfficient conversion of methane to value-added products such as olefins and aromatics has been in pursuit for the past few decades. The demand has increased further due to the recent discoveries of shale gas reserves. Oxidative and non-oxidative coupling of methane (OCM and NOCM) have been actively researched, although catalysts with commercially viable conversion rates are not yet available. Recently, $${{{{{{{\mathrm{Sr}}}}}}}}_2Fe_{1.5 + 0.075}Mo_{0.5}O_{6 - \delta }$$ Sr 2 F e 1.5 + 0.075 M o 0.5 O 6 − δ (SFMO-075Fe) has been reported to activate methane in an electrochemical OCM (EC-OCM) set up with a C2 selectivity of 82.2%1. However, alkaline earth metal-based materials are known to suffer chemical instability in carbon-rich environments. Hence, here we evaluated the chemical stability of SFMO in carbon-rich conditions with varying oxygen concentrations at temperatures relevant for EC-OCM. SFMO-075Fe showed good methane activation properties especially at low overpotentials but suffered poor chemical stability as observed via thermogravimetric, powder XRD, and XPS measurements where SrCO3 was observed to be a major decomposition product along with SrMoO3 and MoC. Nevertheless, our study demonstrates that electrochemical methods could be used to selectively activate methane towards partial oxidation products such as ethylene at low overpotentials while higher applied biases result in the complete oxidation of methane to carbon dioxide and water.

Unraveling Minimum Active Units and Substrate Activation for Carbon Nitride in Photocatalytic Oxidation Reactions

2020 ◽  
Author(s):  
Chaofeng Huang ◽  
Yaping Wen ◽  
Dandan Dong ◽  
Yanfei Shen ◽  
Songqin Liu ◽  
...  
Keyword(s):  
Photocatalytic Oxidation ◽  
Carbon Nitride ◽  
Value Added ◽  
Electronic Coupling ◽  
Oxidation Reactions ◽  
Active Structure ◽  
Substrate Activation ◽  
Condensed Form ◽  
Water Cleaning ◽  
Photocatalytic Reactions

<p>Covalent bonded carbon nitride (CN) has stimulated extensive attentions from photosynthesis to optoelectronics. However, the acquisition of correct numbers beyond stoichiometry and composition remains indefinable. Moreover, the electronic coupling by the substrates to the photoexcitation processes in value-added oxidation reactions is essential, but still poorly understood. Herein, we report by far the minimum active structure of CN by constructing fragments consisting of melem (M1) and its incomplete condensed form with cyanide termination (M2). Surprisingly, such configuration endowed a boosted activity of 11 times of traditional bulk CN in photocatalytic oxidation of tetracycline as a showcase application of water cleaning and sanitation. The mechanism studies disclosed that M1 and M2 were primarily responsible for light absorption and charge separation, respectively;<a></a><a> meanwhile the electronic coupling by the O<sub>2</sub> substrate participated the photoexcited processes thus synergistically enhanced the photocatalytic reactions.</a></p>

Characteristics of the Photocatalytic Oxidation of Methane into Methanol on V-Containing MCM-41 Catalysts

2008 ◽  
Vol 124 (1-2) ◽  
pp. 80-84 ◽  
Author(s):  
Yun Hu ◽  
Yasuhito Nagai ◽  
Diana Rahmawaty ◽  
Chaohai Wei ◽  
Masakazu Anpo
Keyword(s):  
Photocatalytic Oxidation ◽  
Oxidation Of Methane ◽  
Mcm 41
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